Justinas Varanavicius, 31, had also been seen by police to be turning its lights on and off.
He was followed from Bishops Road and pulled over in London Road.
A preliminary test at the roadside indicated 52 microgrammes per 100 millilitres of breath, the legal limit being 35. In custody the reading was 43.
Checks showed Varanavicius had an expired provisional licence and was not insured.
At Peterborough Magistrates’ Court on Monday, he pleaded guilty to drink-driving, driving otherwise than in accordance with a licence and having no insurance on June 19, 2021.
In mitigation, he said: “It’s the craziest mistake I have ever done. I’m really sorry and want to apologise.”
Varanavicius, of Brymore, Bretton, was banned for 12 months, which can be cut with completion of a drink-driver rehabilitation course.
He was also fined £550 and ordered to pay £160 in costs and victim surcharge.